A grand bargain with Iran or a mini-bargain with the Saudis?

Even with all of the recent talk about foreign policy “realism,” one of the major tenets of leading realists (George F. Kennan and Hans Morgenthau come to mind) has gone largely ignored. Most realists subscribe to the view that any state that seeks to accumulate too much power will almost surely provoke a balancing coalition of other states seeking to check the expansion of its influence.
Many realists would argue that the U.S. has experienced this phenomenon to its detriment in the past few years. Some realists would also maintain that if the U.S. is “checked” in Iraq, the same dynamic will come into play against the emerging power in the region — Iran. Under this scenario a coalition, led most likely by Saudi Arabia, will seek to balance Iranian power. The religious divide between Sunni and Shia will help propel the coalition building. Diana West (no “realist” to my knowledge) notes that an adviser to the Saudi government, Nawaf Obaid, has said that in the event of a U.S. withdrawal from Iraq, the Saudi government might try to check the spread of Iranian influence by supporting Iraq’s Sunni fighters and by inducing a drop in oil prices so as to limit Tehrans’s ability to subsidize proxy militias. Diana argues that “a Saudi-Iranian rift over Iraq sounds like a win-win situation for the United States,” especially if accompanied by a drop in oil prices. And she contends that such a scenario provides an alternative to “victory” (probably unattainable) or “cataclysm” in Iraq.
I’d be quite surprised if, in the absence of a U.S. presence in Iraq, the Saudis would be able to counter-balance Iran there. It strikes me as more likely that al Qaeda, if anyone, would serve that function (not that the Saudis and al Qaeda necessarily represent an “either-or”). I’d also be surprised if, without substantial assistance from the U.S., the Saudis or anyone else would be able to check Iranian power in the region as a whole.
I do agree, though, that Sunni-Shia strife in Iraq is not a threat to our security (as long as we’re not in the crossfire) and that certain of Iran’s neighbors are likely to be far better long-term anti-Iran coalition partners than the Europeans. Finally, I note that to the extent James Baker wants to enter into a grand bargian with Iran, he is not only unrealistic, he’s not even a “realist” in the academic, balance-of-power sense.